The 2017 MIME assessment describes the trends and status of contaminant concentrations in biota and sediment at monitoring stations in the OSPAR area. Assessments are made for a large number of time series, each of a single contaminant in a single species (for biota) at a single monitoring station. This document is one of a series that synthesises the results of the individual time series to assess status and trends at the MIME regional level. In particular, it considers PAH concentrations in sediment, where the PAHs are PA, ANT, FLU, PYR, BAA, CHR, BAP, BGHIP, ICDP. For simplicity, the term â€˜regionâ€™ is used throughout to describe MIME regions. OSPAR regions are always referred to as such.

The following sections:

- summarise the individual time series results
- describe the methods used to combine the individual time series results to estimate regional trends and status
- present the estimates of regional trends
- present the estimates of regional status

A time series of PAH concentrations is assessed for status if:

- there is at least one year with data in the period 2010 to 2015
- there are at least three years of data over the whole time series
- a parametric model can be fitted to the data and used to estimate the mean concentration in the final monitoring year (or, occasionally, if a non-parametric test of status is applied)

The conditions are more stringent for trends. Specifically, a time series is assessed for trends if:

- there is at least one year with data in the period 2010 to 2015
- there are at least five years of data over the whole time series
- a parametric model can be fitted to the data and used to estimate the trend in mean concentrations

Note that all trend assessments for individual time series and most status assessments are based on the fit of a parametric model. This is important because only the parametric results are passed into the regional assessments in the following sections. Only 9 of 1597 PAH time series were assessed for status using a non-parametric test.

The first tab below shows all the monitoring stations where there are individual time series assessments of trend or status for PAHs. The magenta circles are stations where there is a trend assessment for at least one PAH, and the cyan cirles are stations where there are only status assessments.

The next set of tabs show the trend and status assessments for each PAH in turn. The colours have the following meaning:

- blue: the mean concentration is significantly (p < 0.05) below the Background Assessment Concentration (BAC)
- green: the mean concentration is significantly (p < 0.05) below the Effects Range Low (ERL)
- red: the mean concentration is not signficantly below the Effects Range Low (ERL)

And the shapes have the following meaning:

- downward triangle: the mean concentration is significantly decreasing (p < 0.05)
- circle: there is no significant change in mean concentration (p > 0.05)
- upward triangle: the mean concentration is significantly increasing (p < 0.05)

The final set of tabs give:

- the number of time series with upwards, downwards or no trend in each MiME and OSPAR region
- the same information presented as proportions
- the number of time series with blue, green, or red status in each MIME and OSPAR region
- the same information presented as proportions

Note that there are no ERLs for BGHIP and ICDP. Time series for these PAHs are only assessed against the BAC, and are coloured blue if significantly below the BAC and orange otherwise.